On Mon, Nov 21, 2022 at 06:11:52PM +0100, Vlastimil Babka wrote: > For tiny systems that have used SLOB until now, SLUB might be > impractical due to its higher memory usage. To help with that, introduce > an option CONFIG_SLUB_TINY that modifies SLUB to use less memory. > This is done by sacrificing scalability, security and debugging > features, therefore not recommended for any system with more than 16MB > RAM. > > This commit introduces the option and uses it to set other related > options in a way that reduces memory usage. > > Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx> > --- > mm/Kconfig | 21 +++++++++++++++++---- > mm/Kconfig.debug | 2 +- > 2 files changed, 18 insertions(+), 5 deletions(-) > > diff --git a/mm/Kconfig b/mm/Kconfig > index 57e1d8c5b505..5941cb34e30d 100644 > --- a/mm/Kconfig > +++ b/mm/Kconfig > @@ -230,6 +230,19 @@ config SLOB > > endchoice > > +config SLUB_TINY > + bool "Configure SLUB for minimal memory footprint" > + depends on SLUB && EXPERT > + select SLAB_MERGE_DEFAULT > + help > + Configures the SLUB allocator in a way to achieve minimal memory > + footprint, sacrificing scalability, debugging and other features. > + This is intended only for the smallest system that had used the > + SLOB allocator and is not recommended for systems with more than > + 16MB RAM. > + > + If unsure, say N. > + > config SLAB_MERGE_DEFAULT > bool "Allow slab caches to be merged" > default y > @@ -247,7 +260,7 @@ config SLAB_MERGE_DEFAULT > > config SLAB_FREELIST_RANDOM > bool "Randomize slab freelist" > - depends on SLAB || SLUB > + depends on SLAB || SLUB && !SLUB_TINY > help > Randomizes the freelist order used on creating new pages. This > security feature reduces the predictability of the kernel slab > @@ -255,7 +268,7 @@ config SLAB_FREELIST_RANDOM > > config SLAB_FREELIST_HARDENED > bool "Harden slab freelist metadata" > - depends on SLAB || SLUB > + depends on SLAB || SLUB && !SLUB_TINY > help > Many kernel heap attacks try to target slab cache metadata and > other infrastructure. This options makes minor performance > @@ -267,7 +280,7 @@ config SLAB_FREELIST_HARDENED > config SLUB_STATS > default n > bool "Enable SLUB performance statistics" > - depends on SLUB && SYSFS > + depends on SLUB && SYSFS && !SLUB_TINY > help > SLUB statistics are useful to debug SLUBs allocation behavior in > order find ways to optimize the allocator. This should never be > @@ -279,7 +292,7 @@ config SLUB_STATS > > config SLUB_CPU_PARTIAL > default y > - depends on SLUB && SMP > + depends on SLUB && SMP && !SLUB_TINY > bool "SLUB per cpu partial cache" > help > Per cpu partial caches accelerate objects allocation and freeing > diff --git a/mm/Kconfig.debug b/mm/Kconfig.debug > index ce8dded36de9..fca699ad1fb0 100644 > --- a/mm/Kconfig.debug > +++ b/mm/Kconfig.debug > @@ -56,7 +56,7 @@ config DEBUG_SLAB > config SLUB_DEBUG > default y > bool "Enable SLUB debugging support" if EXPERT > - depends on SLUB && SYSFS > + depends on SLUB && SYSFS && !SLUB_TINY > select STACKDEPOT if STACKTRACE_SUPPORT > help > SLUB has extensive debug support features. Disabling these can > -- > 2.38.1 Acked-by: Hyeonggon Yoo <42.hyeyoo@xxxxxxxxx> small comment: SLAB || (SLUB && !SLUB_TINY) would be easier to interpret than SLAB || SLUB && !SLUB_TINY -- Thanks, Hyeonggon
